1. Field of the Invention
The present invention relates to a method of managing a solid/gas adsorption or thermochemical reaction allowing the production of cold and/or heat by a solid/gas reaction.
2. Description of Related Art
The thermochemical reaction, or adsorption, is based on a reversible reaction between a solid and a gas of the type: ##STR1##
The reaction is exothermic in direction 1, which means that in this direction it produces heat, and it is endothermic in direction 2; In direction 1, it produces cold by evaporating the gas (G); in direction 2, it may also produce cold if it is carried out in a closed vessel.
Such a system enables energy to be stored in chemical form and has various fields of application.
In addition, such a system makes it possible, using a heat source at a temperature Ts, to produce heat at a temperature Tu such that: EQU Tu&lt;Ts
In this case, the system is called a "chemical heat pump".
Such a system also makes it possible, using a heat source at a temperature T's, to produce heat at a temperature T'u such that: EQU T'u&gt;T's
In this case, the system is called a "chemical thermoconverter".
By virtue of this system, it is possible to produce refrigerating power using a heat source and simultaneously to produce, using a heat source at a temperature T"s, heat at a temperature T"u (T"u&lt;T"s) and refrigerating power.
Depending on the circumstances, the use of the heat or cold produced is simultaneous with the consumption of energy at high temperature (Ts, T's, T"s) or at a later time (storage effect).
Document EP-A-0,382,586 discloses a device for the production of cold and/or heat by a solid/gas reaction, comprising two reactors, forming a reaction chamber, each containing a salt capable of reacting chemically with a gas, a condenser and an evaporator for the gas. The elements of the device are arranged so as to allow the gas to follow a path from one reactor to the other, passing through the condenser and the evaporator. At the end of the chemical reaction, the reactor lean in gas is at a temperature higher than that of the reactor containing the gas which is to react with the salt, the two reactors being at different pressure levels. Heat is sent via a heat-transfer-fluid system from the reactor which is at the higher temperature to the reactor which is at the lower temperature so as to increase the temperature of the latter. The chemical reaction has then taken place in the reverse direction, part of the heat of one reactor serving as a source of heat for desorption of the gas in the other reactor. This transfer of heat between the two reactors serves to improve the efficiency of the system.
In some applications, for example the production of ice, a simpler device may be suitable. Thus, a simplified device may comprise a single reactor, provided with a heat exchanger enabling the solid to be regenerated, it being possible for this reactor to be connected selectively to an evaporator/condenser assembly placed in a water reservoir. Evaporation of the liquid, when the gas reacts with the salt or is adsorbed on the solid in the reactor, causes the formation of ice. When the salt in the reactor is in the synthesis phase, or when the adsorbent is enriched with gas, that is to say reacts exothermically, the heat produced is removed via the heat exchanger. Regeneration of the solid, by heating, at the end of the decomposition or desorption reaction, leads to the evaporator/condenser assembly being reheated by condensation of the gas, this having the result of detaching the ice formed on the outside of the evaporator.
However, the means making it possible to remove the heat of reaction of the salt, or the heat of adsorption of the gas on the adsorbent solid, placed in the reactor, have the drawback of making the device bulky. In addition, the complete cycle, of ice production and salt regeneration, may prove to be very long.